Grid rows and columns in CSS - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ layout

intermediate

What is the number of columns in this grid?

Consider the CSS below. How many columns will the grid container have?

CSS

display: grid;
grid-template-columns: repeat(3, 1fr);

A 3

B 2

C 1

D 4

💡 Hint

The repeat function sets how many columns are created.

The property grid-template-columns: repeat(3, 1fr) creates 3 equal columns.

📝 Syntax

intermediate

Which option correctly defines 2 rows with different heights?

You want a grid with two rows: the first row 100px tall and the second row 200px tall. Which CSS is correct?

A grid-rows: 100px 200px;

B grid-rows-template: 100px, 200px;

C grid-template-rows: 100px, 200px;

D grid-template-rows: 100px 200px;

💡 Hint

The property name is grid-template-rows and values are space-separated without commas.

The correct syntax is grid-template-rows: 100px 200px; Commas are not used and the property name must be exact.

❓ rendering

advanced

What will be the height of the second row?

Given this CSS, what is the height of the second row in the grid container?

CSS

display: grid;
grid-template-rows: 100px auto 50px;

A 100px

B 50px

C auto

D 150px

💡 Hint

The second value in grid-template-rows sets the second row height.

The second row height is set to auto, which means it adjusts to the content height.

❓ selector

advanced

Which CSS selector targets the second column in a grid?

You want to style all items in the second column of a grid container. Which selector will do this?

A .grid-container > :nth-child(2)

B .grid-container > :nth-child(3n+2)

C .grid-container > :nth-child(4n+2)

D .grid-container > :nth-child(2n)

💡 Hint

Grid items are placed row-wise. Use a formula to select every item in the second column.

In a grid with 3 columns, items in the second column are every 3rd item starting at index 2: nth-child(3n+2).

❓ accessibility

expert

How to make a grid accessible for screen readers?

Which practice improves accessibility for a grid layout used as a data table?

A Use semantic <table>, <thead>, <tbody>, and <th> elements instead of divs with CSS grid.

B Add role="grid" to the container and use divs for all cells.

C Use aria-label on each grid cell and no semantic elements.

D Use only CSS grid with no ARIA roles or semantic tags.

💡 Hint

Semantic HTML elements help screen readers understand data tables better than ARIA alone.

Using semantic table elements provides built-in accessibility and keyboard navigation support for data grids.

Practice

1. What does the CSS property grid-template-columns control in a grid layout?

easy

A. The number and width of columns in the grid

B. The number and height of rows in the grid

C. The gap between grid items

D. The background color of the grid container

Solution

1. Step 1: Understand the property name

   The property name grid-template-columns suggests it controls columns.

2. Step 2: Recall grid layout basics

   This property sets how many columns there are and their widths.

3. Final Answer:

   The number and width of columns in the grid -> Option A

4. Quick Check:

   grid-template-columns = columns control [OK]

Hint: Columns = grid-template-columns, rows = grid-template-rows [OK]

Common Mistakes:

• Confusing columns with rows
• Thinking it controls gaps
• Mixing it with background styles

2. Which of the following is the correct syntax to create a grid with 3 columns each 100px wide?

easy

A. grid-template-columns: repeat(3, 100px);

B. grid-template-columns: 3x 100px;

C. grid-template-columns: 100px, 100px, 100px;

D. grid-template-columns: 100px * 3;

Solution

1. Step 1: Identify valid CSS syntax for repeating columns

   The repeat() function is the correct way to repeat values in grid-template-columns.

2. Step 2: Check each option

   grid-template-columns: 100px, 100px, 100px; uses commas (invalid); B: '3x 100px' invalid; C: repeat(3, 100px) correct; D: '* 3' invalid CSS syntax.

3. Final Answer:

   grid-template-columns: repeat(3, 100px); -> Option A

4. Quick Check:

   Use repeat() for repeating columns [OK]

Hint: Use repeat() to simplify repeated column sizes [OK]

Common Mistakes:

• Writing invalid CSS like '3x 100px'
• Using commas between column sizes
• Using multiplication syntax not supported in CSS

3. Given the CSS below, how many rows and columns will the grid have?

display: grid;
grid-template-columns: 150px 1fr 2fr;
grid-template-rows: 100px auto;

medium

A. 2 columns and 2 rows

B. 2 columns and 3 rows

C. 3 columns and 3 rows

D. 3 columns and 2 rows

Solution

1. Step 1: Count columns from grid-template-columns

   There are three values: 150px, 1fr, 2fr, so 3 columns.

2. Step 2: Count rows from grid-template-rows

   There are two values: 100px and auto, so 2 rows.

3. Final Answer:

   3 columns and 2 rows -> Option D

4. Quick Check:

   Count values in columns and rows properties [OK]

Hint: Count values in grid-template-columns and grid-template-rows [OK]

Common Mistakes:

• Mixing up rows and columns count
• Assuming 'auto' adds extra rows
• Ignoring fractional units

4. Identify the error in this CSS grid code:

display: grid;
grid-template-columns: 100px, 200px, 100px;
grid-template-rows: 50px 50px;

medium

A. grid-template-rows must have commas between values

B. Commas should not be used between column sizes

C. display: grid; should be display: grid-container;

D. Column sizes must all be the same unit

Solution

1. Step 1: Check syntax for grid-template-columns

   Values should be space-separated, not comma-separated.

2. Step 2: Verify other options

   grid-template-rows is correct without commas; display: grid is valid; units can differ.

3. Final Answer:

   Commas should not be used between column sizes -> Option B

4. Quick Check:

   Grid values are space-separated, not comma-separated [OK]

Hint: Use spaces, not commas, between grid sizes [OK]

Common Mistakes:

• Using commas between grid sizes
• Changing display property incorrectly
• Thinking units must match

5. You want a grid with 4 equal columns and 3 rows where the first row is 100px tall and the others share remaining space equally. Which CSS is correct?

hard

A. grid-template-columns: repeat(3, 1fr); grid-template-rows: 100px 1fr 1fr 1fr;

B. grid-template-columns: 4fr; grid-template-rows: 100px auto auto;

C. grid-template-columns: repeat(4, 1fr); grid-template-rows: 100px 1fr 1fr;

D. grid-template-columns: 1fr 1fr 1fr 1fr; grid-template-rows: 100px 100px 100px;

Solution

1. Step 1: Set 4 equal columns

   Using repeat(4, 1fr) creates 4 columns each taking equal space.

2. Step 2: Define 3 rows with first fixed and others flexible

   grid-template-rows: 100px 1fr 1fr; sets first row fixed 100px, next two share remaining space equally.

3. Final Answer:

   grid-template-columns: repeat(4, 1fr); grid-template-rows: 100px 1fr 1fr; -> Option C

4. Quick Check:

   repeat() for columns, fixed + fractional rows [OK]

Hint: Use repeat() for equal columns and 1fr for flexible rows [OK]

Common Mistakes:

• Wrong number of columns or rows
• Using auto instead of 1fr for equal space
• Setting all rows fixed height